Chapter 10 Inheritance of Characterstics and Genetic engineering Flashcards
how many chromosomes does the body cells have
they have 23 pairs of chromosomes each of which contains a DNA molecule
what is DNA divided into
DNA can be divided into a large number of genes each of which codes for a particular protein
what do females have
females have 22 pair of chromosomes plus 2 X chromosomes
what do males have
males have 22 pair of chromosomes plus one X and one Y chromosome
the Y chromosomes is not …
genetically identical to the X chromosome
what is mitosis
in the division of body cells mitosis ensures that exact copies of the chromosomes are passed to 2 daughter cells which are genetically identical
what is meiosis
during gamete formation 4 cells are produced by meiosis each of which contains half the number of chromosomes
gametes are all
genetically different
what do the chromosomes carry
the genetic information form parents to offspring
what is a change in a chromosome or single gene called
a mutation
what does a mutation result in
loss of an enzyme, which disrupts the cells chemical reactions or its structure the effect may be minor but could lead to genetic disorders
how are characteristics inherited
through the chromosomes which are passed on from the mother and father, the offspring receives a mixture of genes from both parents
allele genotype phenotype homozygous heterozygous dominant recessive
allele - different version of the same gene
genotype - the genes you have
phenotype - the characteristics that are displayed
homozygous - two alleles the same
heterozygous - two alleles different
dominant - only one needs to be present for it to be expressed
recessive - 2 needs to the present for it to be expressed
what can alter a charactersitc
lifestyle - diet and exercise
how are sex link cells inherited
through the mother, fathers cannot pass a sex linked disorder to their sons because the boys inherit y chromosomes
why might disorders that usually appear in males but can appear in females
if a boy has an x chromosome that has a mutated allele then he will have the disorder even though its recessive
if the girl has one fauty allele she will also have the normal dominat allele and wont develop the disorder
colour blindness
haemophilia - blood does not clot properly
muscular dystrophy - the muscles gradually degenerate
some disorders can be down to
the loss or duplication of part of or a whole chromosome
insulin thing
a human gene can be transferred to bacterial DNA using specific enzymes and the process can be sued to manufacture hormones such as insulin and vaccines
experimental techniques
genes can be transferred to human cells in gene therapy to treat diseases like cystic fibrosis
stem cells can be sued to replace damaged tissue
what are the benefits of genetic engineering
- get rid of disorders
- slippery slope
what are the benefits of gene therapy
- problems occur
- expensive
- stop genetic disorders
what are the benefits of stem cell therapy
- get rid of genetic disorders
what are the benefits of embryo screening
- get rid of genetic disorders
- cost the government a lot of money
what is huntingtons disease
it causes degeneration of brain cells
dominant allele
what is cystic fibrosis
its a genetic disorder where the person produces a very thick sticky mucus
recessive disorder
what do genetic counsellors do
these are health professionals who use their understanding of the mechanisms of inheritance to advise parents on the chances of a child being born with a genetic disorder
